Lose weightOr if you're at an ideal body weight now, stay there. Extra weight puts a strain on your heart and other crucial body systems; increasing the risk of heart attacks, diabetes, cancer and other diseases that can shorten life, says Robert Butler, director of the International Longevity Center-USA in New York. Most Americans simply eat too much: The experts recommend cutting back on calories, a step that will help trim the waistline and, if drastic enough, might even extend life.

Learn something new Take up ballroom dancing, chess, a language or photography. "Any time you have to work at something new you're probably doing good things for your brain," says Gene Cohen, director of the Center on Aging at the George Washington University in Washington, D.C. People who learn new skills or information probably build new brain cells and make connections between existing neurons, he says.

Shape up Research suggests that regular exercise can help prevent or delay a laundry list of diseases, including heart disease, colon cancer, diabetes and even Alzheimer's. The experts say most Americans should aim for at least 30 minutes of moderately intense exercise 5 days a week or more. And it's never too late to start a fitness program, says Richard Hodes, director of the National Institute on Aging. Even seniors who've never been active before can work up to a fitness routine that will help keep them strong for years to come. Walking, swimming, dancing — even gardening and housework — can help people stay in shape, he says.

And here's one area where people can start to turn back the clock: Research shows most people lose 22% of their muscle mass by age 70, a process that leaves them prone to deadly falls. People can reverse that aspect of aging with simple, daily strength exercises.

If you smoke, stop In the USA alone, tobacco-related diseases cause more than 400,000 deaths a year. Yet nearly 50 million Americans still smoke.

Socialize Go to a party, join a movie club, help out at a church picnic. Research suggests that people who build and maintain friendships and family relationships often are healthier and seem to recover from illness faster. Social connections may ward off depression and seem to boost the body's immune system, which helps fight infection.

Reduce stressTake a walk, pray, meditate or have lunch with a friend. Scientists say that people who build stress-busting habits into their daily routine gain a big health benefit. Unhealthy stress puts people at risk of getting sick or developing chronic diseases that can cut life short.

Adopt a can-do attitude Research shows that people who live to be 100 often take an optimistic approach to life's setbacks. Super-agers either are born with a happy-go-lucky personality that helps them through the inevitable stress that life brings or they develop coping mechanisms that help them weather upsets like a death or a divorce.

Eat a healthy dietDiets that include at least 10 servings of fruits and vegetables per day might help prevent age-related damage to cells. Fruits and veggies, the more colorful the better, contain protective substances that might help ward off diseases such as cancer and heart disease.

Most longevity experts recommend cutting down on fatty, salty foods. Go for lean meats, poultry and fish, as well as a wide variety of fresh fruits, veggies and whole grain foods.

Get a good night's sleepNew research shows that sleep deprivation can lead to memory lapses, depression and immune system problems. Scientists say that sleep deprivation may not be a natural part of aging.

Get regular checkupsFind a good doctor and make good health a priority, says Christine Cassel, the president of the American Board of Internal Medicine and an aging expert in Philadelphia. Many diseases like diabetes, high blood pressure, heart disease and others can be treated or even prevented if caught early enough, she says.